Abstract

To clarify the effects of drying temperature on the hygroscopicity and mechanical performance of MUF resin-impregnated wood, we investigated the water vapor adsorption capability, modulus of rupture (MOR), modulus of elasticity (MOE), and surface hardness of MUF resin-impregnated wood treated at 60, 80, 100, 120, 140 °C. Drying temperature can influence the hygroscopicity of MUF resin-impregnated wood. As temperature increased, hygroscopicity typically decreased, but the resin-impregnated wood hygroscopicity increased after treatment at 60 °C. Drying temperature has shown significant influence on the mechanical performance of MUF resin-impregnated wood (α = 0.01). Increasing the treatment temperature can enhance the mechanical performance of resin-impregnated wood. However, brittleness of the resin-impregnated wood increased after treatment at 140 °C. Characterization of FTIR and ¹³C CP/MAS NMR indicate that higher drying temperature led to lower content of hydroxymethyl groups and more substituted reactive sites on the amino group. This refers to more complete dehydration condensation between the resin active groups, thereby increasing the crosslinking density of the resin, increasing the cohesive strength, and decreasing the hygroscopic groups.

摘要

为了阐明干燥温度对 MUF 树脂浸渍木材的吸湿性和机械性能的影响，我们研究了 MUF 树脂浸渍的水蒸气吸附能力、断裂模量 (MOR)、弹性模量 (MOE) 和表面硬度。在 60、80、100、120、140 °C 下处理的木材。干燥温度会影响 MUF 树脂浸渍木材的吸湿性。随着温度的升高，吸湿性通常会降低，但在 60°C 处理后，树脂浸渍木材的吸湿性会增加。干燥温度对 MUF 树脂浸渍木材的机械性能有显着影响（α = 0.01）。提高处理温度可以提高树脂浸渍木材的机械性能。然而，在 140°C 处理后，浸渍树脂的木材的脆性增加。FTIR 的表征和¹³ C CP/MAS NMR表明较高的干燥温度导致较低的羟甲基含量和氨基上更多的取代反应位点。这是指树脂活性基团之间脱水缩合更完全，从而提高树脂的交联密度，提高内聚强度，减少吸湿基团。